Telephone-exchange system



T 1, 2,0 June 1927' w. w. CARPENTER 63 56 TELEPHONE rsxcmmes SYSTEM Filed April 2. 1924 4 Shets-S'heet 1 llll 1,6 2, June 14, 1927. w. w. CARPENTER 3 I056 TELEPHONE EXCHANGE SYSTEM Filed April 2. 1924 4 Sheets-Sheet 3 mg [U III I I llll - j 1,632,056 June 1927' w. w. CARPENTER TELEPHONE EXCHANGE SYSTEM Filed April 2. 1924 4 Sheets-Sheet 4 Patented June 14, 1927.

UNITED STATES ENT 'LIOFFIC'E.

WARREN W. CARPENTER, oiF QUEiENs, NEWY-ORK, :ASSIGN OR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF -N YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Application flied April 2, 1924. Serial No. 703,679.

This invention relates to' telephone exchange systems and more especially to systems employing automatic switching apparatus in the establishment of conversational 52 coni'iections between subscribers lines.

In systems using automatic switches of the coordinate or cross bar type where a comparatively large number of contacts are involved in the talking circuit it is desirable to H ascertain the condition of these contacts each time'a connection is established to a subscribersline. It the contacts are all functioning properly and are closed when the switches areain their operated condition then 3 it is proper to proceed with the application of ringing current to signal the wanted party. On the other hand if one or more of the switch contacts tail to operate and this unstandard condition is apprehended in advance the application of ringing current may be withheld and the proper signals given to the central oliice attendants.

Accordingly it is the object of this invention to make a test ot the contacts of the switches employed in the establishment of a in contacts of the operated switches and the ca led line loop together with means for applying a source of current to the test circuit to determine if it is continuous.

Another feature relates to the provision of signal which becomes effective in case the test reveals an open point in the test circuit and means also for preventing the application of ringing current-to operate the called subscribefls'bell in such an event.

Referring, to the drawing, Figs. 1, 2 and 3 taken in order and Fig.4 placed below Fig.1 illustrate a portion of a telephone exchange system incorporating the principles of this invention.

Fig. 1 shows diagrammatically subscribers lines terminating in a line switch and one of the number of outgoing trunks and also a sender selector switch.

Fig. 2 shows a part of a first group selector or district selector switch together with one of a number of trunks shown in detail leading out from the district switch. This figure also shows a portion of one of a number of switch controlling markers. 7 3 illustrates an incoming selector as shown in the drawing.

and also a sender connector for connectingthe different senders with the markers shown in Fig. 2. r I

The line switch 101, district selector 200, incoming selector 300, connector switch 307 and the sender selector switch 103 are all of thecoordinate type such as fully described in detail in the patent to S. B. lVilliams No.

1,517,331, grantedDecember 2, 192$. The particular application of these switches to a telephone system and the controlling apparatus employed for operating the same as herein illustrated are more fully described in my copending application, Serial No.

1703,362 filed April 1, 1924-, and whenever details otopera'tion are referred to hereinafter and not specifically shown, reference is hereby made to said application for an understanding thereof.

The 'calling subscribers lines terminate in the line switch 101 in vertical rows such as row 109. Trunks such as trunk 102 appearing in the vertical row'of contacts 110 lead vto district selector switches 200. The trunk 102 seento'appear in the vertical row 201 of the'particular district selector shown in the drawing.

The district selector switches have groups of outgoing trunks appearing in vertical rows. The group of trunks including trunks 204', 205 and 206 appearin the vertical row 203 of switch 200 while second group is illustrated occupying the vertical row 202. The trunks from the district selector switch may lead to distant oliices or, as illustrated in I which is shown in detail appears'in the vertical row 301 of the incoming selector switch Other trunks from the same or other district selector switches may appear in other vertical rows of contacts. I

The incoming selector 300 also has a num ber of groups of trunks outgoing therefrom and terminating in vertical rows of contacts of connector switches such as switch 307. One of these trunks 321 belong to the group appearing in the row .303 1 extends to and ion occupies the vertical row 308 in the connector switch 307. The connector switch has a number of vertical rows of contacts 309, 310 in each of which-appears a group ofsubscribers lines. T

The trunks extending from the line switch 101 and from other line switches'appear in the sender selector switch 108 which in turn has access to a number o1 register senders one of which is partially illustrated at the left of Fig. 4.

For the purpose of connecting the register senders with thc marlrers shown within the large brolzen rectangle in Fig. 2, there is provided a sender connector device 400. This connector is made up of a number of multicontact relays 410, 411, etc. each individual to a different one of the senders. Furthermore, the connector 400 comprises a number of multi-contact relays 412, 413, etc. each representing a different one of the controlling markers. By operating two of these multi-contact relays, the particular sender may be connected to the particular marker represented.

The marker has associated therewith a final translator 315 which cooperates with the marker to determine the selective operation of the connector switch 307. There is provided a connecting device 314 which serves to associate the final translator 315 with the connector 307. There is also provided a multi-contact relay connecting device 813, the function of which is to associate the marker with the incoming selector switch 300 for the purpose of selectively operating the same.

The calling subscriber, by manipulating his dial, transmits series of impulses to the sender which are recorded upon a set of registers 409. Later, when the sender is associated with the marker this record is transferred from the registers 409 to a similar set of registers 224 in the marker. With the record thus established in the marker this latter mechanism determines the selective oporation of the incoming selector 300 and the connector switch 307 to complete the calling line through to the wanted line such as line inasmuch as this connection involves two sets of contacts in the switch 300 for both the tip and ring conductors and'also two sets of contacts in the connector switch 307 for both the tip and ring conductors, it is especially desirable to determine whether the connection is completed at every point before ringing current is applied to the called subscribers line. This purpose is accomplished by applying a source of alternating current 222 over the tip and ring conductors leading through the incoming switch 300 and the connector switch 307 and including the loop of the called subscribers line. If the test circuit is complete in every particular, the controlling apparatus is discharged in with an idle sender.

the usual manner and ringing current is thereupon applied to signal the called subscribers station. If, however, the testing circuitis found open, the marker is not released immediately, but awaits the completion of a time measure counting device and thereupon sends the proper signal back to the sender which causes the operation of an alarm signal before an operator or attendants position.

Considering the operation of the system in detail it will be assumed that the subscriber of line 100 desires to converse with the subscriber 01 line The calling subscriber upon initiating the'call causes the line switch 101 to operate thereby extending his line to an idle trunk 102 leading to the district selector switch 200. The initiation of the call also causes the operation of the sender selector switch 103 which associates trunk 102 During the operation of the sender selector switch 103, relay 104 is energized and the tip and ring of the call ing subscribefis line are extended over conductors 111 and 112 through the sender selector switch 103 through the windings respectively of the balancing coil 401 and the impulse relay 402. Relay 402 operates the slow release holding relay 404. Relay 404 applies ground potential to the conductor and thereby provides a holding circuit for relay 104. The slow release relay 107 also operates and applies a holding ground potential to the conductor 113.

The subscriber operates his transmitter and records the wanted designation on the registers 409 of the appropriated sender. The sender is thereupon associated with a marker, not shown, which controls the operation of the district selector 200 and extends the trunk 102 to an idle trunk 204 in the proper group leading to the incoming selector switch 300.

After the district selector is operated the sender is disassociated from the first marker and a relay 407 operates for the purpose of associating the sender with the marker shown in the drawing. Relay 407 completes a circuit from ground through its right contact, upper winding of relay 414, contact of relay 421, battery at the outer right contact of relay 415. Relay 414 operates and closes a circuit from battery through the winding of relay 415, lower front contact and winding of relay 414 to ground at the contact of relay 407. Relay 41.4 locks and relay 415 operates in this circuit. Relay 415 causes the operation of the multi-contact relay 410 in a circuit from battery through the winding of relay 410, upper contact of relay 414, conductor 423, to ground at the left contact of relay 415.

Relay 414 also operates the relay 418, provided the first marker represented by the multi-contact relay 413 is idle. The circuit for this purpose may be traced from ground through the lower contact of relay 414, contact of relay 416, uppercontact of relay 417, contact of relay 410, lower back contact of relay 417, upper winding ofrelay 418, to battery at the back contact of relay 419. Relay 418 operates and a circuit is completed from battery through the winding off'rclay 419, contact and lower winding of relay 418, and thence to ground at the contact ofrelay 414. Relay 418 locks and relay 419 operates in this circuit. Relay 419 opens the original circuit for relay418 anda-lso operates the relays 417 and 416. The circuit for relay 417 may be traced from ground, through the 'middle contact of relay 419, upper winding of relay 417, to battery. Relay 417'operatc's and identifies the associated marker as busy. The circuit for relay 416 may be traced from ground, through the middlejcontact ofqrelay 419, lower contact of'relay 4:18, winding of relay 416, to battery.

The multi-contact relay 413 is operated in a circuit from battery through its winding, contact of'relay 418, contact of relay 419, to ground. lVith relays 410 and 413 operated, the various leads frorn the sender are eX- tended through the connecting device 400 to the marker illustrated within the large broken rectangle in Fig. 2.

Upon the association of the sender with the marker, the marker start relay 216 is energized in acircuit from battery, through the winding thereof, thence to the connect ing device 400 to ground at the contact of relay 407. i I

The next operation is to transfer the numerical record from the registers 409 of the sender to corresponding registers 224 in the marker. Upon 'receivingthe numerical record, the marker proceeds to selectanidle trunk in the proper, group extending from the incomingswitch300, an idle horizontal "link in said switch, and an idle horizontal link in the connectorswitch 307, which has acccssto the called subscribers line 322. For instance, if the trunk 321 is idle and the associated link 325 in the incoming selector switch 300 is also idle, this trunk will be taken forfuse. If, for example, the link 326 at theconnector switch is idle, it will be appropriated for. the purpose of connecting the trunk 321 to the called :line 322.

For the purpose of enabling the marker to control the incoming switch 300, it is connected thereto through the medium of the frame connector 313, as will presently be described. At the time the'district selector 200 selects the trunk 204, the relay 207 is operated in a circuit from battery throughthe winding of said relay, back contact of relay 208, conductor 225, thence through the switch 200 to the grounded sleeve conductor 113- At the time the marker is connected to the sender, acircuit is-extended from the marker through the sender and thence through the sender selector 103, conductor 114, upper contact of relay 108, over the tip conductor of the trunk through the switch 200, upper front contact of relay 207, lower winding of relay-215, to battery. Relay 215 operates and operates the vertical magnet 304 "in a circuit leading from battery, through the winding of said magnet, inner upper contact of relay 214,to ground at the "bottom contact of relay 215. Belay 215 also operates the niulti-contact relay 316 of the frame connector in a circuit from battery,

.through the winding of said multi-contact relay,upper contact of relay 215, to ground at the bottom contact ofrelay 214.

. When the marker is connected to the senderand relay 216is operated, a circuit is completed for operating-the relay 320 associated with the frame connector 313. This circuit may be traced from ground, through the upper-contact of relay 318, upper wind-- ing of relay 320, contact ofrelay 220, to battery at the lower contactof relay 216.

Belay 320 operates and olosesa locking circuit from ground through the winding of relay 318, back contact of relay 319, lower front contact and lower winding of'relay 320, to battery as above traced. Relay 318 operates in this circuit to prevent the subsequent operation of other relays, such as the relay 319. Relay 317 is now operated in a circuit from battery through its winding, upper contact of relay 320, toground at the front contact of relay 318.

WVith relays 316" and 317 operated, the marker is associated with the selector switch 300 and the conductors 327 are extended for the purpose of testing the horizontal trunks in the switch 300 and for operating the The connection having been extended, a

test will now be made to ascertain whether all contacts involved 111 the talking connection extending throughthe switches 300 and 307 are properly operated before ringing current is applied to the called line. For this purpose, a circuit may be traced from the source of alternating current 222, relay 221, conductor 226, through the connector 313, conductor 330, upper contact of relay 212, lower contact of relay 211, thence over .414 and 415.

the ring of the trunk 204, through contacts of the switch 300, thence over the ring of trunk 321, through contacts of the switch 307, thence over the loop of the called subscribers line 322, and returning over the tip side of the line through the switches 307 and 300, to ground at the upper back contact of relay 211. The frequency of the source 222 may be of any suitable Value which will not cause the operation of the subscribers bell. The subscribers line at this time is open to prevent the flow of direct current, wherefore the alternating current must flow over the usual ringing circuit. If the test circuit is complete at every point, the relay 221 responds to the flow of current in the circuit and operates the relay 223. The circuit for relay 223 extends from-battery, through its winding, contact of relay 221, conductor 227, to ground at the upper contact of relay 216. Relay 223 locks through its lower contact to the grounded conductor 227. With relay 223 operated and with the release relay 219 energized, which takes place as soon as i the connection has been effected, a circuit is closed for operating the release relay 228 This circuit may be traced from battery. through the upper winding of relay 228, upper contact of relay219, upper contact of relay 223, to the grounded conductor 227. Relay 228 locks through its lower winding and operates the relay 218 in a circuit completed at its upper front contact. Relay 213 serves to send an indication back to the sender enabling the sender to release, since it is no longer required for this call. The circuit for this purpose may be traced from ground, over conductor 227, contact of relay 218, conductor 220, through the connector 400, winding of release relay 405, to battery. Relay 405 operates and in well known manner brings about the release of the register sender.

Relay 407 releases upon the release of the sender and opens the circuit of the relays These relays release and in turn cause the release of relays 419, 418, 417, 410, 413 and 416. The release of the sender connector 400 also causes the release of the relay- 216 in the marker, whereupon the marker itself is restored to normal ready for subsequent connections.

As hcrcinbefore stated, the horizontal magnet 306 is operated by means of a circuit completed in the marker. This circuit leads as above traced over conductor 329 and thence to ground in the marker. hen the magnet 306 operates the switch 300, it completes a circuit from battery, through both its windings in series, thence through the contacts of the switch in the row 301, over the sleeve conductor 230 of the trunk 204, winding of relay 208, to ground over the sleeve conductor 225. Due, however, to the fact that the conductor 329 is grounded in the marker, relay 208 is short circuited and does not operate. \Vhen, however, the

marker subsequently releases, the ground poing equipment involved in establishing a connection through'the switches 300 and 307, are restored at the time the marker is disconnected.

, Relay 208 in operating, operates the relay 212 in a circuit from battery, through the winding of said relay, inner lower back contact of relay 211, contact of relay 210, front contact of relay 208, to the grounded conductor 225. On the next closure of the upper contact of the interrupter 213, relay 214 is operated in a circuit from battery through its winding and make-before-break contact, lower contact of relay 212, to ground through the upper contact of interrupter 213. Relay 214 looks through its lower contact to ground on conductor 231. On the closure of the lower contact of the interrupter 2133, relay 215 is re-operated in a circuit from battery, through its upper winding and contact, middle upper contact of relay 214, to ground at the lower contact of interrupter 213. Relay 215 looks at the grounded conductor 231.

When relay 212 first operated, a momentary application of ringing current was applied over the following circuit: from the ringing source 232, back contact of relay 215, winding of relay 210, upper front contact of relay 212, bottom contact of relay 211, over the ring side of the line and returning over the tip side of the line, to

ground at the upper contact of relay 211. lVhen relay 215 later operates, this source is disconnected and ringing current is intermittently applied over the following circuit: from the ringing source 233, uppermost contact of relay 214, lower front contact of relay 215, winding of relay 210, and thence over the path previously traced, including the called subscribers station. Relay 210 being marginal, does not operate in this circuit. During the application of ringing current, a circuit exists which may be traced from battery, through the winding of relay 211, front contact of relay 208, to the grounded conductor 225. Relay 211 is shunted, however, by means of a circuit through its inner upper contact, through its inner lower contact, contact of relay 210, to ground.

When the called subscriber answers, the

resistance is reduced. and relay 2 operates to remove the shunt, permitting the relay 211 to operate. .Relay211' disconnects ringing current and completes the talking conductors for conversation; Relay 211 releasesthe relays 212, 214uand 215. Relay 212 opens the circuit of'rel'ay 210, and this relay becomes deenergized.

Ii, however, at the timethe test is made of the called subscribers loop, a complete circuit is not found to exist, the relay 221 fails to operate. Relay 221 by failing to operate, prevents the operation of relay 218 and consequently prevents the marker from sending a signal back to the sender to cause the release of the latter. At the time the marker is taken into service, a time measuring device is set in operation to cover a given interval of time within which the marker is supposed to complete its regular functions. This device is represented by an interrupter 234. If the test of the called subscribers loop reveals that the same is not complete and the marker is held from releasing for a time longer than the regular interval, the relay 217 is operated in a circuit from battery, through the winding of said relay, lower contact of the interrupter 234, to ground at the contact of relay 216. When the interrupter 234 again closes its upper contact, a circuit is completed from ground, through the contact of relay 216, upper contact oi interrupter 234, lower contact of relay 217, thence over conductor 235, through the sender connector 400, winding of relay 406 to battery. Relay 406 looks to ground at the contact of slow-to-release relay 404. Relay 406 may causethe operation of a signal lamp 408 at a monitoring operators position or may operate any other suitable signal to advise the attendant of the existing trouble. The monitoring operator by attending to the trouble, may cause the dis charge of the sender.

When troubleis encountered as above related the marker does not release and consequently ground is not removed from conductor 329 in order to permit relay 208 to operate. Since relay 208 cannot operate ringing current is withheld from the called line.

2. In a telephone system, a telephone line, a selective switch having contacts, meansv for operating the contacts of said switch to extend a connection tosaid line, a sender for controlling" the selective operation of said switch,- a signal,\means for testing the condition of the connection extended through the contacts of said switch to the telephone line, andi'neans in said sender re spon-sive to the test thus made for operatng said signal. I

3. a telephonesystem,a telephone line, a selective switch having contacts, a register sender for recording designations, a marker cooperating with said sender to selectively control said switch, means for operating the contacts 01'? said switch to extend a talking connection to said line, and means for testing the condition of the connection extended before such connection can be used for conversation.

4. In a telephone system, a subscribers line, a selective switch having contacts, a plurality of senders each arranged to record designations, a plurality of markers each associable with said senders and serving to control the selective operation of said switch, means for operating the contacts of said switch under the control of one of said markers'to extenda talking connection to said line, and means for testing the extended connection to ascertain whether it is continuous before such connection can be placed in condition for conversation.

5. The combination in a telephone system of a telephone line, a selective switch havingoperable contacts, a sender for recording designations, a marker cooperating with said sender and arranged to selectively control the operation of said switch, means for operating the contacts of said switch under the control of said marker to extend a talking connection to said line, and means in the marker for testing the condition of the connection extended to determine if such connection is suitable for conversation.

6. The combination in a telephone system of a subscribers line, a selective switch having contacts, a sender for registering designations, a marker coacting with the sender for controlling the selective operation of said switch, means for operating the contacts of said switch to extend a talking connection to said line, and a source of alternating current in said marker for testing the condition of the extended connection be inc fore such connection can be used for conoperationof said switch, means for operat-' 10 ing the switch contacts to extend a talking connection to said line, means in said marker for making a test of the continuity of the extended connection before such connection can be placed in condition for conversation, and a trouble signal rendered effective by said testing means if the extended connection is not complete.

In witness whereof, I hereunto subscribe my name this 27th da of March A. D., 1924.

WARRE W. CARPENTER. 

